Control system for well production line



Jan. 30, 1968 R. A. COTTRELL CONTROL SYSTEM FOR WELL PRODUCTION LINE Filed Feb. 1, 1966- .u U; E n T k 0 n C 1 7/ .9/ .7 R .4 W 0 T T R ;l firm .w W Y B e I @EU mm 9 1 :2 r y m 3 mm 5960mm mozmwmo L E mzoo 10:26 k8 15 6528 IIIIIIJ w 2mm wumnom $201 (2 United States Patent Office 3,366,063 CONTROL SYSTEM FOR WELL PRODUCTION LINE This invention relates to production of petroleum and, more particularly, to production of petroleum from wells which intermittently produce liquids.

In the production of petroleum, a problem exists in wells which produce a mixture of liquid and gas inasmuch as, under normal operation, it is desirable to shut down the well if the well is not producing liquid. This problem has been in existence and recognized for a considerable period of time and various solutions have been suggested therefor; e.g. Tipton US. Patent No. 2,316,494, issued Apr. 3, 1943, presents the problem and suggests the solution that the oil he accumulated in a reservoir and the bottom of the reservoir be pumped with a small, separate pump. Also, in my prior patent application, Ser. No. 424,892, filed Ian. 12, 1965, now Patent No. 3,274,940, I suggested another solution of having a pressure control valve with a small port therethrough to accumulate liquids in a reservoir mounted above the pipe.

The present invention solves the problem by having a pipeline with a downstream portion of the pipe located at a lower elevation. Fluid is then withdrawn from the bottom of the pipe at a higher elevation and conducted through a small line and re-introduced into the pipe downstream at a lower elevation. The flow through the line conducting the withdrawn fluid is restricted, as for example, by a valve which is manually adjusted. Upstream from the manually-adjusted valve is a float chamber. If the oil well is producing a greater flow rate of oil than will pass through the manually-adjusted valve, oil will accumulate in the float chamber. Once having detected presence or absence of an accumulation of oil in the float chamber, it is a simple procedure to shut down the well responsive to this indicator.

An object of this invention is to provide a device for detecting whether a pre-set minimum flow rate of liquid is flowing through a pipe.

Another object is to shut down an oil well if it is not producing a pre-determined amount of liquid.

Still further objects are to achieve the above with a device that is sturdy, compact, durable, simple, versatile, and reliable, yet inexpensive and easy to manufacture and operate.

Still further objects are to achieve the above with a method that is rapid, inexpensive, and does not require skilled people to adjust, install and operate.

The specific nature of the invention, as well as other objects, uses, and advantages thereof, will clearly appear from the following description and from the accompanying drawing, which schematically illustrates an embodiment of my invention.

Referring more particularly to the drawing, pump is located far beneath the surface of the earth 'within oil well 12. The pump is actuated through pumpjack 14 located on top of the ground, which is powered by electric motor 16. The electric motor receives its power from power source 18 is provided switch 20 is closed. The switch 20 is controlled by switch operator 22 which itself is controlled by remote controller-computer-recorder 24.

The fluids produced by the well 12 will flow through pipe 26 from the well to a remote locationin this case, tank 28.

The pipe 26 extends to an elevated position shown as elevated horizontal section 30. The purpose for having the section 30 elevated will be explained later. Down- 3,366,063 Patented Jan. 30, 1968 stream from the elevated section 30 is a section 32 of the pipe 26 which has a lower elevation than the elevated section 30. Inlet of line 34 is connected to the elevated section 30 at the bottom of the pipe. Outlet of the line 34 is connected into the lower section 32 of the pipe. The line 34 has valve 36 therein by which the flow of liquid through the line 34 may be restricted to any desired amount. Float chamber 38 is upstream from the valve 36. The float chamber is an enlargement in the line 34 or it has an increased volume from the size of the line 34 itself.

Float 40 within the float chamber 38 is a means for detecting if there is an accumulation of liquid within the float chamber 38. If there is no accumulation of liquid within the float chamber, the float will be in its lower-most position. However, if there is an accumulation of liquid within the float chamber 38, the float 40 will rise. Therefore, the float detects if there is an accumulation of liquid within the float chamber. This information may be transmitted through an electrical signal within wires 42 by a switch attached to the shaft of the float 40.

The wires 42 are connected to the remote controllercomputer-recorder 24 whereby the presence or absence of a signal in the wires 42 indicates whether the well 12 is producing a greater amount of liquid than will flow by the valve 36. If a greater amount of liquid is being produced by the well than will flow by valve 36, the well is permitted to continue to produce. However, if the production of liquid is less than will flow by valve 36, there will be no accumulation of liquid within the float chamber and, therefore, there will be a diflerent indication at the remote controller-computer-recorder. In this instance, the well 12 will be shut down by sending a signal to the switch operator 22 which opens the switch 20.

The system is shown with electrical controls and switch operators. Those skilled in the art will understand that it could be used to be operated pneumatically to shut down a gas lift-operated well by cutting off the flow of gas to the mechanism. Furthermore, if the well 12 flows freely without the use of any pump mechanism 10, it will be understood that the controller could operate a valve (either electric or pneumatic) in the pipe 26 adjacent to the well to shut down the well by this means.

Normally, the petroleum produced by an oil well will contain entrained gases which are released as the petroleum is produced, in which case there will be gas flowing through the pipe 26 and there will be no problem of trapping liquids within the float chamber 38. The pressure upstream always will be greater than the pressure downstream for the normal flow of fluids. Therefore, as long as the outlet of the line 34 is a lower elevation than the inlet of the line 34, any oil within the float chamber 38 Will be draining constantly from the float chamber.

However, if -a dead liquid is being produced from the well (by dead liquid I mean a liquid without any entrained gases), it might be possible to produce a vaccum at the elevated section 30 of the pipe 26 which would prevent the flow of liquids from the float chamber 38. In that event, it is necessary that the elevated section 30 'be higher than the discharge 44 of the pipe 26 into the tank 28. Stated otherwise, one must ensure that there is no vacuum or blockage of the liquid within the float chamber. This may be done in either of two ways-by operating with a liquid that has gas in it or by constructing the system so that it will drain.

The equipment described is well known to the art and further explanation need not be given. Also, it will be understood by those skilled in the art that the pipe 26 also has additional valves 46 and 48 and check valve 50-. Likewise, the line 34 has additional valve 52 and check valve 54.

3,366,063 3 4 It will be apparent that the embodiment shown in only (n) control means connected to said float means for exemplary and that various modifications can be made in shutting down said well responsive to the detection construction, materials, and arrangement within the of fluids in said float chamber. scope of the invention as defined in the appended claims. 2. The invention as defined in claim 1 with the addi- I claim as my invention:

1. In a petroleum production system including:

(a) an oil well and (b) a pipe attached to the well for fluidly conducting fluids produced by said well to a remote point;

(c) the improvement comprising in combination with 5 tion of:

(0) means operatively associated with the system for preventing a vacuum -from occurring in the pipe at the point the inlet of the line attaches to the pipe.

3. The invention as defined in claim 2 wherein (p) said control means is an electrical remote conthe above: 10 troller-computer-recorder.

(d) a line having 4. The invention as defined in claim 2 wherein (e) its inlet fluidly attached to the bottom of said pipe (p) said float chamber has an enlarged volume from and said line,

(f) its outlet fluidly attached to said pipe at an eleva- 15 (q) said line being much smaller than said pipe, and tion below the inlet, (r) a valve in said line downstream from said float (g) said outlet being downstream in the pipe from chamber.

Said inlet References Cited (h) a float chamber in said line,

(j) said float chamber lower than the inlet of said line 20 UNITED STATES PATENTS 4/1943 Tipton 103-25 X 3/1956 Leslie 137399 X ALAN COHAN, Primary Examiner. 

1. IN A PETROLEUM PRODUCTION SYSTEM INCLUDING: (A) AN OIL WELL AND (B) A PIPE ATTACHED TO THE WELL FOR FLUIDLY CONDUCTING FLUIDS PRODUCED BY SAID WELL TO A REMOTE POINT; (C) THE IMPROVEMENT COMPRISING IN COMBINATION WITH THE ABOVE; (D) A LINE HAVING (E) ITS INLET FLUIDLY ATTACHED TO THE BOTTOM OF SAID PIPE AND (F) ITS OUTLET FLUIDLY ATTACHED TO SAID PIPE AT AN ELEVATION BELOW THE INLET, (G) SAID OUTLET BEING DOWNSTREAM IN THE PIPE FROM SAID INLET, (H) A FLOAT CHAMBER IN SAID LINE, (J) SAID FLOAT CHAMBER LOWER THAN THE INLET OF SAID LINE AND (K) HIGHER THAN THE OUTLET OF SAID LINE, (M) FLOAT MEANS IN SAID FLOAT CHAMBER FOR DETECTING THE PRESENCE OF LIQUIDS IN SAID CHAMBER, AND (N) CONTROL MEANS CONNECTED TO SAID FLAT MEANS FOR SHUTTING DOWN SAID WELL RESPONSIVE TO THE DETECTION OF FLUIDS IN SAID FLOAT CHAMBER. 